If we're talking about manufacturing more efficiently, there's an upper limit to where that's going to get us with the resources we have here on earth. Granted, I think the resources here are sufficient to maintain a stable population with minimal work in perpetuity, but since that situation won't come about overnight, looking at the road by which we get there is a big deal - the arguments by Lemur866 only make sense to me if it happened overnight, and if costs actually got down to near-zero, which I don't see happening without energy to matter conversion, if such a thing is even possible at any point in the future.

First, we see products get cheaper and cheaper, but at the same time less and less jobs are available. Manufacturing jobs mostly vanish entirely - at some point even slave labor would be less efficient than having the machine do it (in many industries that's already the case, in the rest it will be eventually). Service and entertainment jobs are all that remains, and many of those start going to the robots too. Eventually, the cost of having a robot flip a burger and serve it to the customers is less than the cost of hiring someone. At this time, we're still running on increased amounts of government welfare most likely, but there's increasing resentment to that from all the corporation owners and higher ups.

Still, there's a large number of jobs that still needs doing - business, science, and software engineering, and entertainment. Most of the robots still need people to write their initial programs for them and so on. These are the companies' real customers at this point, since they're the only ones still making more than welfare (which we'll remember, is being taken from the companies in the first place - they'd rather keep it than give it away and then be given it back in return). Eventually, people write programs that can automate the entire business sector (technically, this may have been an even earlier step, but it still happens at some point or another). Some time after that comes the real trick - someone comes up with a program that can program other programs. Robots no longer need people to write their programs for them, that process is automated. Software engineering goes away as a sector of employment, we're left only with the scientists and entertainers - these would eventually be replaced too, but societal unrest is likely to change things before that happens.

By this time, we've probably got 75%+ of the population unemployed, producing nothing, only consuming. Those who are still employed are resentful of them - they don't want these people taking what they have. Why? Human nature. Logic suggests that everyone could have 'enough' easily by this point, but most people seem to want way more than 'enough'. A multi-billionaire today has no need to increase their assets, yet they continue to do so. The same will apply at this point - those who are still making money will want to make more money, and they won't want to give away their money to people who are completely useless to them. Since government is primarily made up of the rich, the government will be on their side. The idea will be that anyone can be a scientist or an actor/writer/other form of entertainer. Those who don't do that are lazy, they don't deserve as much welfare as they're getting. Goods still have value, because we're not creating them from essentially limitless energy, star trek replicator style, and although their value is low enough that everyone could theoretically have most things they want, those who are still earning money that's being taxed and redistributed want to reduce what they're paying.*

Welfare and taxes are slowly reduced, or perhaps money is devalued through intentional inflation - inflation that goes up faster than the welfare numbers. Prices go up since there's more money in circulation, but the welfare remains the same numerically, so the masses of unemployed can afford less and less of the luxuries they want. Widespread unrest probably follows at this point. With increasing violence from the unemployed masses, stricter laws are put into place, and pretty much everyone still making money gets themselves a little army of private security bots to ensure their safety. Eventually, the unemployed will probably revolt. Unfortunately by this time, the security bots are far too advanced and commonplace for them to have a chance. Millions or even billions will probably die in unsuccessful revolutions - eventually the survivors would be either imprisoned or simply exiled to undesirable regions. Some of the earners would sympathize and perhaps even side with them, but it seems unlikely to be a large enough number to turn the tide in their favor.

The remaining earners would continue to exist as they do, their workload probably diminishing more slowly at this point. Eventually entertainers or scientists are replaced - hard to say which - when the robots are able to take over those fields. Programs will eventually be written to discern human tastes, and robots will be able to create entertainment based purely on the data they receive. It may not be as creative as some of what we have seen, but it will be satisfactory. Science too, will eventually be a robotic field, since it is primarily concerned with studying empirical data, something computers do well. New ideas will still have to be thought up by people, but they will be along the lines of 'hey robot, I want a thing that can do <insert neat thing the human just thought of>' and the machines will determine how to implement that request.

By the time entertainers and scientists are replaced, there will likely be minimal friction in simply allowing the robots to continue taking care of them. Besides which, everyone will have sufficient money to continue 'paying' for their upkeep for a significant amount of time, at this juncture. Land is the only thing that will still have value, and this will primarily go to those who owned and produced the robots throughout this entire transition. As population rises again, the land will be broken up into smaller and smaller chunks as it is divided among children, then grandchildren, and so on. And life will be good, at least until they run out of room and/or resources they can't figure out a way to replace or do without.

*Again, for the same reason that billionaires today continue to acquire more wealth even though there's no real need for it: someone who has 10 billion could stop earning money forever, and spend $273,972.60 a day for 100 years - with a more reasonable expenditure of $27,397.26 a day, the 10 billion would last a thousand years, or drop down one more decimal to $2,739.72 a day to make it last ten thousand years. Enough for them and all their foreseeable heirs - and inflation seems unlikely to take us to the point where that much daily expenditure will provide anything less than an 'extremely comfortable' lifestyle for centuries. Yet, people with billions keep trying to make more billions.